Encapsulated/air-free crushing and mash production

ABSTRACT

A plant and a process for crushing and mash production is provided wherein the raw material to be processed is broken up and mashed in a mill system. Prior to the mill system ( 1 ) being filled with the material ( 6 ) to be crushed the mill system is filled with an inert gas from a gas reservoir ( 13 ) so that the atmospheric oxygen in the mill system ( 1 ) is substantially displaced. After the mill system ( 1 ) has been filled, the latter is sealed in substantially gas-tight manner and the raw material ( 6 ) is ground and mashed in, subject to exclusion of atmospheric oxygen.

FIELD OF THE INVENTION

The invention relates to crushing and mash production with a view to thepreparation of beer in a brewery, the raw material to be processed beingbroken up in a mill system and then mashed in.

BACKGROUND OF THE INVENTION

The beer-preparation process begins in its first phase with the crushingof the raw materials. In this phase the raw material arriving forprocessing is broken up in a malt mill, for example in a hammer mill,roll mill or disc mill, and is transformed, according to demand, into acrushed malt of highly diverse composition and consistency. In thecourse of the breaking-up of the raw material arriving forprocessing—for example, malt, barley, millet or the like—the variousconstituents of the raw material are exposed, by reason of thestructural transformation, to the atmospheric oxygen that is present inthe atmosphere within the malt mills. This results in oxidationprocesses and enzymatic activities which have a negative influence onthe beer-preparation process, since they have effects impairing flavourand stability.

Further oxidation of the raw-material constituents occurs in the courseof the subsequent mashing-in of the crushed raw material at the end ofthe mill system. Since the activity of the enzymes and the associatedoxidation processes are intensified considerably in the course ofmashing-in as a result of the addition of water, the undesirableoxidation of the raw materials in the premashers used for mashing-in, inthe doughing screws, in the mash pumps and in the mash vessel iscontinued and intensified. All the more so, since by reason ofbrew-specific properties the temperature of the admixed water in thecourse of mashing-in is around the optimal temperature for theeffectiveness of the enzyme groups.

SUMMARY AND OBJECTS OF THE INVENTION

It is therefore an object of the present invention to make available aprocess for crushing and mash production in a mill system, whereinoxidation of the raw materials employed as a result of crushing andmashing-in is minimized or eliminated. It is a further object of theinvention to make available a plant for crushing and mash production inwhich the process according to the invention can be carried out. Theseobjects are achieved by means of a process having the features of theinvention.

With the process according to the invention the mill system is filledwith an inert gas prior to being filled with the raw material to becrushed. The atmospheric oxygen in the interior of the mill system issubstantially displaced by the inert gas. This means that substantiallyno atmospheric oxygen is present any longer in the mill system prior tothe mill system being filled. After the immediately ensuing filling ofthe mill system from the raw-material silo the mill system issubstantially sealed in gas-tight manner. This sealing of the millsystem relates to all parts of the plant where atmospheric oxygen couldpenetrate unhindered into the mill system, that is to say, inparticular, into the charging shaft for the supply of raw material. Thetransition of the mill system to the mash vessel situated downstream issealed by the liquid in the pipelines and in the mash pump. As a result,crushing and mashing-in of the raw materials is then effected in themill system, which is encapsulated in gas-tight manner, in asubstantially oxygen-free atmosphere of inert gas oxidation of particlesof raw material can therefore be greatly, minimized.

During the filling of the mill system with raw material from theraw-material silo the mill system has to be opened for a short time. Asa result, some air is able to penetrate into the mill system through theraw-material supply. Some atmospheric oxygen is also introduced into theplant with the raw material that is supplied. In case, with a view tofurther quality enhancement, displacement of this residual oxygen or ofresidual oxygen that has penetrated as a result of other smaller leaksis desired, the mill system can subsequently be flushed, at leastzonally, with inert gas. In this way atmospheric oxygen that haspenetrated during the filling of the mill system or via other leaks isdisplaced. To this end, excess gas volume is pressed out of the millsystem by means of inert-gas overpressure, for example. Flushing withinert gas may also be continued after the start of the crushing andmashing-in process. As a result of this it is possible for the entirecrushing and mashing-in process to be managed in a controlled inert-gasatmosphere. Hence, during the production process only slight traces ofatmospheric oxygen are available, and undesirable oxidation processesare substantially avoided.

It is particularly advantageous to generate an inert-gas atmospherehaving an inert-gas overpressure in the mill system. As a consequence ofthis overpressure no atmospheric oxygen is able to penetrate into theplant as a result of small leaks which may be present. The designtolerances with respect to the impermeability of the plant to gas maytherefore be made wider, permitting a reduction in cost in connectionwith the manufacture of the requisite plant components.

The inert gas should be fed into the plant with an overpressure in therange from 2 to 100 mbar. In this connection the plant should exhibitsufficient impermeability to gas in order to be able substantially tomaintain this overpressure.

By way of inert gases, use may be made of all gases that prevent, or atleast minimize, oxidation of the raw materials during the crushing andmashing-in processes and that at the same time are unobjectionable asregards food technology. It is particularly advantageuos, however, toemploy an inert gas that is heavier than air. If the inert gas isheavier than air, the atmospheric oxygen in the mill system is displacedupward by reason of the higher specific weight of the inert gas. Inertgas that is introduced into the mill system collects at the lowest pointof the mill system and, proceeding from here , fills up the mill system.The residual air which may be contained in the mill system consequentlyfloats on a cushion of inert gas and can therefore be displaced furtherand further upward simply by adding further quantities of inert gas.This has advantages, particularly when the plant is not to be flushedwith a current of inert gas after being filled with raw materials. Inthis case, oxygen introduced with the raw material can be displacedupward in the plant by the heavier inert gas to a location whereoxidation of the raw materials is not to be feared, since the rawmaterials have not yet been broken up.

Since the process according to the invention serves to produce afoodstuff, carbon dioxide, nitrogen or similar gas mixtures shouldpreferably be used by way of inert gases. These gases have sufficientoxidation-inhibiting action to prevent the undesirable oxidation of theraw materials. Since these gases are also contained proportionately inrespiratory air, no relevant toxic effect arises by reason of theinfluence of these inert gases on the raw materials.

Particularly preferred is the use of nitrogen obtained from air by meansof a preceding gas-separation process. Since air has a high nitrogencontent, this inert gas can be produced from air in sufficient purityand very cost-effectively with the aid of a gas-separation process. Byway of gas-separation process, use may be made, for example, of membraneseparation processes that are known as such. Production of the nitrogenfrom air has the advantage, moreover, that the plant thereby presents anequalized emission balance with respect to the inert gas. Nitrogen thatis discharged from the plant mixes again with the air from which thenitrogen was previously separated. Overall no nitrogen is emitted fromexternal sources. In principle it is immaterial, according to theinvention, in which direction the inert gas flows when the mill systemis flushed. The direction of the current is primarily determined bywhere inert gas is supplied and at which point of the mill system excessinert gas is able to flow out, since the gas flows from the inletopenings to the outlet openings. It is particularly preferred to directthe current of the inert gas in the mill system contrary to thedirection of motion of the raw material during the crushing andmashing-in process. As a result the gas flows towards the particles ofraw material and can therefore wash around the raw materials inparticularly effective manner and can in particular also displaceatmospheric oxygen that is bound to the surface of the particles of rawmaterial. In addition, if the inert gas is heavier than air, theupward-directed current assists the displacement of the oxygen upward asa consequence of the higher specific weight. The outlet opening shouldtherefore be arranged as high as possible in the mill system and theinlet opening for the inert gas should be arranged as low as possible.

The process according to the invention is primarily provided for thepurpose of displacing atmospheric oxygen from the mill system. However,according to the invention it is also readily possible to incorporatethe mash vessel situated downstream of the mill system into the processfor displacing atmospheric oxygen. To this end the mash vessel has to beconnected to the gas supply in a manner equivalent to that of the millsystem and has to be pressurized prior to being filled with inert gas.After being filled with inert gas the mash vessel should then likewisebe encapsulated in gas-tight manner in order to prevent penetration ofoxygen. Hence the atmospheric oxygen is also displaced from the mashvessel, and undesirable oxidation processes on the surface of the mashand of the mash vessel are prevented.

The mash vessel either may be directly connected to the gas supply ormay be provided with inert gas indirectly via the mill system. If themash vessel is supplied indirectly, a special pressure-regulation systemfor the mash vessel may be dispensed with. Differing pressures in themill system and in the mash vessel which would press the mash from onepart of the plant into the others are prevented by means of anequalisation of gas pressure between mash vessel and mill system.

According to the invention it is sufficient to fill the mill system witha certain quantity of inert gas and possibly to flush it subsequently inunregulated manner with a fixed quantity of inert gas in order todisplace the atmospheric oxygen. Better utilization of the requisitequantity of inert gas and more complete prevention of the undesirableoxidation processes are possible, however, by the flushing of the millsystem with inert gas being regulated as a function of the residualcontent of atmospheric oxygen. In this connection the gas composition ismeasured with sensors at one or more points of the mill system and thesupply of inert gas is regulated as a function of this composition.Consequently no inert gas is wasted, and at the same time it is ensuredthat the residual content of atmospheric oxygen does not exceed apermissible value.

Plants for operating the process according to the invention may bedesigned in substantial parts like conventional mill systems.Conventional mill systems are charged via a raw-material supply with rawmaterials to be processed which are subjected within the plant to acrushing and mashing-in process and are transferred in the form of mashthrough the mash outlet into the mash vessel. According to the inventionthese conventional mill systems should be modified in such a way thatthe outer wall of the plant of the mill system is encapsulated insubstantially gas-tight manner and the supply of raw material is capableof being shut off with a substantially gas-tight packing element. Thisresults in a mill system that presents no relevant leakage pointsthrough which atmospheric oxygen can penetrate in relatively largequantities and in uncontrolled manner.

The plant according to the invention must furthermore comprise a gassupply with which the interior of the plant can be pressurized withinert gas. Via the gas supply the interior of the plant can be filledwith inert gas, in which connection an inert-gas atmosphere is formed inthe interior of the plant and the atmospheric oxygen is displaced.During the filling of the plant with inert gas or raw material, excessportions by volume of the gas atmosphere in the interior of the plantescape to the outside via an opened valve or the like. After thecharging with inert gas and raw material the plant is encapsulated ingas-tight manner and no atmospheric oxygen is able to penetrate into themill system.

If it is also intended for the atmospheric oxygen that has beenre-introduced into the plant with the supplied raw material to bedisplaced with a view to quality enhancement, the gas supply should beopened again after the filling with raw material and, as a consequenceof the overpressure resulting therefrom, gas is pressed outward from theinterior of the plant at a valve or the like and the interior of theplant is flushed with inert gas as a result. The atmospheric oxygenintroduced with the raw material can consequently be removed from theinterior of the plant. The supply of gas should also be continued duringthe further crushing and mashing-in process, so that penetration ofatmospheric oxygen is effectively prevented by means of an internalpressure, and changes of volume as a consequence of the withdrawal ofmash are compensated. According to the invention the inert gas orgas/air mixture issuing from the plant can be collected and eitherdischarged into the open air or transferred to a recovery plant with aview to further use.

If it is also intended for the production process in the mash vessel tobe managed subject to exclusion of oxygen, the mash vessel likewise hasto be capable of being shut off in gas-tight manner. The inert gas maybe supplied directly from the gas supply system or indirectly via themill system. In this connection an equalization of pressure between thetwo plant components should be provided, in order to preventdifferential pressures. The packing element for shutting off the supplyof raw material may be constructed in particularly simple manner in theform of a substantially gas-tight flap valve. Flap valves of this typeare known in principle and merely have to be modified to the effect thata gastight packing joint is provided between the flap valve and the wallof the raw material supply obviously it is sufficient to supply theinert gas at only one point of the plant. However, with regard to a morefavorable control of the plant it is advantageous to arrange inletopenings for the supply of inert gas in the malt hopper and/or in theconditioning shaft and/or in the mill body. Hence the plant can befilled with inert gas from bottom to top and, if required, aparticularly effective, upward-directed current of inert gas can beformed during the crushing and mashing-in process. In order to achieve abetter distribution of gas, several inlet openings for the supply ofinert gas may be provided in each part of the plant. If a separate gassupply is provided in each of the various parts of the plant it is inaddition possible to flush individual parts of the plant, for examplethe mill body and the conditioning shaft, very rapidly with inert gas bymeans of an intense admission of gas so that the crushing and mashing-inprocess can begin immediately, without having to wait for totaldisplacement of the atmospheric oxygen also from the malt hoppersituated above. Generally speaking, the displacement of the atmosphericoxygen can be influenced more effectively if separate inlet openings forthe gas supply are provided in all parts of the plant. In the mill bodythe inlet opening for the supply of inert gas should preferably bearranged in the region between malt mill and mash. The raw materials tobe processed are broken up in the malt mill and are thereforeparticularly susceptible to oxidation immediately thereafter. Thereforethe particles of raw material in this region should be washed with inertgas in particularly intensive manner, in order as far as possible toprevent oxidation with residual oxygen which may be present. If theresidual content of atmospheric oxygen in the plant is to be regulated,sensors for measuring the gas atmosphere must be arranged in the variousregions of the plant, in accordance with the regulating algorithm. Withthese sensors it is possible for the composition of the gas atmospherein the respective regions to be determined and for the supply of inertgas to the individual regions of the plant to be regulated on the basisof these data.

Since, according to the invention, the plant is constructed insubstantially gas-tight manner and inert gas is supplied via a gassupply, a safety valve should be provided in the plant for protectionagainst excessive overpressures or underpressures. It for example, toomuch inert gas is supplied unintentionally, impermissibly highoverpressures may build up. In order to prevent damage to the structuralcomponents it is therefore necessary in this case to let off theoverpressure building up via a safety valve. This safety valve or asecond safety valve must also be opened in the event of excessiveunderpressures within the plant. Since volume is permanently removed asa result of the withdrawal of mash during the mashing-in process, anunderpressure can build up in the plant in the event of inadequatefurther provision of inert gas.

It is particularly advantageous to measure the internal pressure in theinterior of the plant permanently and, by means of a regulator, totrigger a controllable inlet valve for inert gas and also a controllableoutlet valve, depending on the internal pressure. By virtue of thisregulating circuit a constant overpressure of inert gas in the plant canbe ensured, irrespective of the state of other aspects of the productionprocess. Impermissible overpressures and underpressures are then alsoruled out.

It is particularly preferable if the plant is capable of being deaeratedvia a surge tank. By draining off the water that has been poured in, alarge cross-section can be opened in such surge tanks, thus facilitatingor accelerating emission of the displaced air from the plant, forexample in the course of filling the plant with inert gas prior to thesupply of raw material. All other degasification processes may also beaccelerated by displacing the corresponding gases via the opened surgetank.

According to the invention, valves may be provided in the gas-supplypipelines so that the gas supply overall is enabled by shutting off themain supply and/or the gas supply to individual parts of the plant isenabled by shutting off the respective supply line. To this end, use maybe made in particular of valves that are infinitely adjustable and/orcapable of being operated electrically. The invention is elucidated inmore detail below on the basis of a drawing representing merelypreferred embodiments of a plant according to the invention.

The various features of novelty which characterize the invention arepointed out with particularity in the claims annexed to and forming apart of this disclosure. For a better understanding of the invention,its operating advantages and specific objects attained by its uses,reference is made to the accompanying drawings and descriptive matter inwhich preferred embodiments of the invention are illustrated.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 in schematic view of the structure of a first embodiment of aplant according to the invention for crushing and mash production; and

FIG. 2 in schematic view of the structure of a second embodiment of aplant according to the invention for crushing and mash production.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in particular, a mill system 1 of theinvention has a malt hopper 2, a conditioning shaft 3 and a mill body 4can be charged with the raw material 6 from a raw-material silo, whichis not represented, via the raw-material supply 5. The raw material 6 isprocessed within the mill system in a crushing and mashing-in process,and the mash 7 is pumped by the mash pump 8 into a mash vessel, which isnot represented, via the mash outlet 9.

If the mill system is to be freshly charged, according to the inventionfirstly the surge tank 10 is drained so that the air contained in theinterior of the plant can escape in an unpressurized manner at thispoint. After the shut-off valves 11 and 12 in the main supply have beenopened, the inert gas flows across from the gas reservoir 13 into thesupply-line system 14. Now the valves 15, 16 and 17 are opened inascending sequence, and the inert gas, which is heavier than air, fillsthe plant in ascending manner, starting from the lowest point. Borne bythe cushion of inert gas, the air contained in the interior of the plantis conveyed from the interior of the plant to the outside through theopened surge tank 10. As soon as all the air has been displaced from theinterior of the plant by the inert gas, the surge tank 10 is closed andthe malt hopper 2 is filled with raw material via the raw-materialsupply. As soon as sufficient raw material has been supplied, thepacking valve 18 is closed so that no air whatsoever is able topenetrate into the interior of the plant from outside.

Inert gas can be conveyed into the interior of the plant via the inletopenings 19, 20 and 21. By virtue of the additional volumetric portionsof the inert gas that has been fed in, an overpressure ruling out anypenetration of air from the external atmosphere is built up in theinterior of the plant.

The actual crushing and mashing-in process is then started by startingthe feed roller 22 and the squeeze roller 23. Since volumetric portionsare permanently lost as a result of withdrawal of mash from the millsystem after the mashing-in process has been started, steps have to betaken to prevent an underpressure arising in the interior of the plant,by virtue of which air would be drawn in again from outside. To this endthe internal pressure of the plant is measured with the pressure gauge24 and inert gas is continually supplied by opening thepressure-regulating valve 12, so that a constant overpressure of inertgas always prevails in the interior of the plant. Should impermissibleoverpressures arise in the plant, they are let off via a safety valvewhich is not represented.

FIG. 2 shows a second embodiment of a plant according to the inventionwhich coincides in substantial parts with the first embodiment. However,the mash vessel 25 is connected to the gas supply indirectly via themill system by way of the line 28. Hence the mash vessel can also befilled with inert gas and, if required, flushed with inert gas. The mashvessel can be sealed in gas-tight manner with the flap valve 26.Deaeration of the mash vessel is effected through the outlet 29, withflap valve 26 opened. In addition, the plant has an extended system forregulating the internal pressure. Depending on the internal pressure,the pressure regulator 24 acts not only on the inlet valve 12 but alsoon the outlet valve 27. Consequently not only underpressures but alsooverpressures in the plant can be readjusted to a target value.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the principles ofthe invention, it will be understood that the invention may be embodiedotherwise without departing from such principles.

What is claimed is:
 1. A process for crushing and mash production, theprocess comprising: providing a mill system; breaking up and mashing rawmaterial to be processed in the mill system; filling the mill systemwith an inert gas to displace the atmospheric oxygen in the mill systemprior to the mill system being filled with the material to be crushed;and sealing the mill system in a gas-tight manner after the mill systemhas been filled with the material to be crushed.
 2. The process forcrushing and mash production according to claim 1, wherein during acrushing and the breaking up and mashing the mill system is flushed atleast zonally with inert gas so that atmospheric oxygen penetratingduring the filling with the material to be crushed is displaced.
 3. Theprocess for crushing and mash production according to claim 1, whereinan inert-gas overpressure is generated in the mill system.
 4. Theprocess for crushing and mash production according to claim 3, whereinthe overpressure lies in the range from 2 to 100 millibar.
 5. Theprocess for crushing and mash production according to claim 1, whereinthe inert gas is heavier than air.
 6. The process for crushing and mashproduction according to claim 1, wherein the inert gas is one or more ofcarbon dioxide, nitrogen or gas mixtures including carbon dioxide andgas mixtures including nitrogen.
 7. The process for crushing and mashproduction according to claim 1, wherein the inert gas includes nitrogenobtained from air in a gas-separation process.
 8. The process forcrushing and mash production according to claim 1, wherein the millsystem is flushed with inert gas by directing inert gas in a directionsubstantially opposite to a direction of transport of the raw material.9. The process for crushing and mash production according to claim 1,wherein a mash vessel is situated downstream of the mill system and isshut off in gas-tight manner and is then pressurised with inert gas. 10.The process for crushing and mash production according to claim 1,wherein the mash vessel a situated downstream of the mill system and isalso flushed with inert gas.
 11. The process for crushing and mashproduction according to claim 1, wherein the flushing of the mill systemwith inert gas is regulated as a function of the residual content ofatmospheric oxygen.
 12. A plant for crushing and mash production, theplant comprising: a raw material supply; a mash outlet; devices forcrushing and mashing-in of the raw materials; an inert gas supply; andshut off and pressurization means for shutting off the entire plant gastightly and pressurizing the plant with inert gas via said inert gassupply.
 13. A plant for crushing and mash production according to claim12, further comprising: a mash vessel; and a mash vessel shut off andpresurization means for shuting off said mash vessel in a gas-tightmanner and for pressurizing said mash vessel with inert gas via saidinert gas supply. 14.The plant for crushing and mash productionaccording to claim 12, wherein said shut off and presurization meansincludes a substantially gas-tight flap valve shutting off saidraw-material supply.
 15. The plant for crushing and mash productionaccording to claim 12, further comprising an inlet opening for thesupply of inert gas arranged in a malt hopper and/or in a conditioningshaft and/or in a mill body.
 16. The plant for crushing and mashproduction according to claim 15, wherein said inlet opening for thesupply of inert gas is arranged in said mill body in a region between amalt mill and mash material.
 17. The plant for crushing and mashproduction according to claim 15, further comprising a probe formeasuring the gas atmosphere, said probe being arranged in the malthopper and/or conditioning shaft and/or in the mill body.
 18. The plantfor crushing and mash production according to claim 12, furthercomprising at least one safety valve for protection against overpressureand/or underpressure, said safety valve being arranged in the plant. 19.The plant for crushing and mash production according to claim 12,further comprising: at least one controllable inlet valve for the supplyof inert gas; at least one controllable outlet valve; and a controlsystem, said inlet valve and said outlet valve both being connected tosaid control system for regulating the internal pressure of the plant.20. The plant for crushing and mash production according to claim 12,further comprising a surge tank, wherein the plant is capable of beingdeaerated via said surge tank.
 21. The plant for crushing and mashproduction according to claim 12, further comprising valves wherein thegas supply is capable of being shut off by said valves at a main supplyand/or at individual inlet openings of various parts of the plant.